On systems booting with ACPI, the IOMMU drivers require the same
kind of id mapping carried out with a DT tree through the of_xlate()
API in order to map devices identifiers to IOMMU ones.

On ACPI systems, since DT nodes are not present (ie struct
device.of_node == NULL), to identify the device requiring the translation
the struct device_node (and the structure used to pass translation
information - struct of_phandle_args - that contains a struct device_node)
cannot be used, so a generic translation structure to be used for IOMMU
mapping should be defined, based on the firmware agnostic fwnode_handle
type.

This patch mechanically refactors/renames the of_xlate API to make
it DT agnostic, by declaring a new type (struct iommu_fwspec), that
allows the kernel to pass a device identifier (fwnode - which can
represent either a DT node or an IOMMU FW node) and by changing the
of_xlate signature so that it does not take anymore the DT specific
of_phandle_args argument and replaces it with the DT agnostic
iommu_fwspec one.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
Cc: Matthias Brugger <matthias....@gmail.com>
Cc: Will Deacon <will.dea...@arm.com>
Cc: Hanjun Guo <hanjun....@linaro.org>
Cc: Rob Herring <robh...@kernel.org>
Cc: Krzysztof Kozlowski <k.kozlow...@samsung.com>
Cc: Robin Murphy <robin.mur...@arm.com>
Cc: Tomasz Nowicki <t...@semihalf.com>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Marek Szyprowski <m.szyprow...@samsung.com>
---
 drivers/iommu/arm-smmu.c     | 12 +++++++-----
 drivers/iommu/exynos-iommu.c | 11 +++++++----
 drivers/iommu/mtk_iommu.c    | 13 ++++++++-----
 drivers/iommu/of_iommu.c     | 20 ++++++++++++++++++--
 include/linux/iommu.h        | 24 ++++++++++++++++++++----
 5 files changed, 60 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 6c42770..84bcff7 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1440,18 +1440,20 @@ out_unlock:
        return ret;
 }
 
-static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
+static int arm_smmu_fw_xlate(struct device *dev, struct iommu_fwspec *args)
 {
        struct arm_smmu_device *smmu;
-       struct platform_device *smmu_pdev;
+       struct platform_device *smmu_pdev = NULL;
+
+       if (is_of_node(args->fwnode))
+               smmu_pdev = of_find_device_by_node(to_of_node(args->fwnode));
 
-       smmu_pdev = of_find_device_by_node(args->np);
        if (!smmu_pdev)
                return -ENODEV;
 
        smmu = platform_get_drvdata(smmu_pdev);
 
-       return arm_smmu_add_dev_streamid(smmu, dev, args->args[0]);
+       return arm_smmu_add_dev_streamid(smmu, dev, args->param[0]);
 }
 
 static struct iommu_ops arm_smmu_ops = {
@@ -1468,7 +1470,7 @@ static struct iommu_ops arm_smmu_ops = {
        .device_group           = arm_smmu_device_group,
        .domain_get_attr        = arm_smmu_domain_get_attr,
        .domain_set_attr        = arm_smmu_domain_set_attr,
-       .of_xlate               = arm_smmu_of_xlate,
+       .fw_xlate               = arm_smmu_fw_xlate,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
 };
 
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 5ecc86c..84ff5bb 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1250,13 +1250,16 @@ static void exynos_iommu_remove_device(struct device 
*dev)
        iommu_group_remove_device(dev);
 }
 
-static int exynos_iommu_of_xlate(struct device *dev,
-                                struct of_phandle_args *spec)
+static int exynos_iommu_fw_xlate(struct device *dev,
+                                struct iommu_fwspec *args)
 {
        struct exynos_iommu_owner *owner = dev->archdata.iommu;
-       struct platform_device *sysmmu = of_find_device_by_node(spec->np);
+       struct platform_device *sysmmu = NULL;
        struct sysmmu_drvdata *data;
 
+       if (is_of_node(args->fwnode))
+               sysmmu = of_find_device_by_node(to_of_node(args->fwnode));
+
        if (!sysmmu)
                return -ENODEV;
 
@@ -1290,7 +1293,7 @@ static struct iommu_ops exynos_iommu_ops = {
        .add_device = exynos_iommu_add_device,
        .remove_device = exynos_iommu_remove_device,
        .pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,
-       .of_xlate = exynos_iommu_of_xlate,
+       .fw_xlate = exynos_iommu_fw_xlate,
 };
 
 static bool init_done;
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 929a66a..e08dc0a 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -436,20 +436,23 @@ static struct iommu_group *mtk_iommu_device_group(struct 
device *dev)
        return data->m4u_group;
 }
 
-static int mtk_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
+static int mtk_iommu_fw_xlate(struct device *dev, struct iommu_fwspec *args)
 {
        struct mtk_iommu_client_priv *head, *priv, *next;
        struct platform_device *m4updev;
 
-       if (args->args_count != 1) {
+       if (!is_of_node(args->fwnode))
+               return -ENODEV;
+
+       if (args->param_count != 1) {
                dev_err(dev, "invalid #iommu-cells(%d) property for IOMMU\n",
-                       args->args_count);
+                       args->param_count);
                return -EINVAL;
        }
 
        if (!dev->archdata.iommu) {
                /* Get the m4u device */
-               m4updev = of_find_device_by_node(args->np);
+               m4updev = of_find_device_by_node(to_of_node(args->fwnode));
                of_node_put(args->np);
                if (WARN_ON(!m4updev))
                        return -EINVAL;
@@ -469,7 +472,7 @@ static int mtk_iommu_of_xlate(struct device *dev, struct 
of_phandle_args *args)
        if (!priv)
                goto err_free_mem;
 
-       priv->mtk_m4u_id = args->args[0];
+       priv->mtk_m4u_id = args->param[0];
        list_add_tail(&priv->client, &head->client);
 
        return 0;
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 910826c..331dd78 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -135,6 +135,18 @@ struct iommu_ops *of_iommu_get_ops(struct device_node *np)
        return ops;
 }
 
+static void of_phandle_args_to_fwspec(struct of_phandle_args *iommu_data,
+                                     struct iommu_fwspec *fwspec)
+{
+       int i;
+
+       fwspec->fwnode = iommu_data->np ? &iommu_data->np->fwnode : NULL;
+       fwspec->param_count = iommu_data->args_count;
+
+       for (i = 0; i < iommu_data->args_count; i++)
+               fwspec->param[i] = iommu_data->args[i];
+}
+
 static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
 {
        struct of_phandle_args *iommu_spec = data;
@@ -148,6 +160,7 @@ struct iommu_ops *of_iommu_configure(struct device *dev,
                                     struct device_node *master_np)
 {
        struct of_phandle_args iommu_spec;
+       struct iommu_fwspec fwspec;
        struct device_node *np = NULL;
        struct iommu_ops *ops = NULL;
        int idx = 0;
@@ -170,8 +183,9 @@ struct iommu_ops *of_iommu_configure(struct device *dev,
 
                iommu_spec.np = np;
                iommu_spec.args_count = 1;
+               of_phandle_args_to_fwspec(&iommu_spec, &fwspec);
                ops = of_iommu_get_ops(np);
-               if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec))
+               if (!ops || !ops->fw_xlate || ops->fw_xlate(dev, &fwspec))
                        goto err_put_node;
 
                of_node_put(np);
@@ -189,7 +203,9 @@ struct iommu_ops *of_iommu_configure(struct device *dev,
                np = iommu_spec.np;
                ops = of_iommu_get_ops(np);
 
-               if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec))
+               of_phandle_args_to_fwspec(&iommu_spec, &fwspec);
+
+               if (!ops || !ops->fw_xlate || ops->fw_xlate(dev, &fwspec))
                        goto err_put_node;
 
                of_node_put(np);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 0bba25e..5184d81 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -85,6 +85,24 @@ struct iommu_domain {
        void *iova_cookie;
 };
 
+#define IOMMU_MAP_SPEC_PARAMS 16
+
+/**
+ * struct iommu_fwspec - generic IOMMU specifier structure
+ *
+ * @fwnode:            Pointer to a firmware-specific descriptor
+ * @param_count:       Number of device-specific parameters
+ * @param:             Device-specific parameters
+ *
+ * This structure, directly modeled after of_phandle_args, is used to
+ * pass a device-specific description of an IOMMU mapping.
+ */
+struct iommu_fwspec {
+       struct fwnode_handle *fwnode;
+       int param_count;
+       u32 param[IOMMU_MAP_SPEC_PARAMS];
+};
+
 enum iommu_cap {
        IOMMU_CAP_CACHE_COHERENCY,      /* IOMMU can enforce cache coherent DMA
                                           transactions */
@@ -155,7 +173,7 @@ struct iommu_dm_region {
  * @domain_window_disable: Disable a particular window for a domain
  * @domain_set_windows: Set the number of windows for a domain
  * @domain_get_windows: Return the number of windows for a domain
- * @of_xlate: add OF master IDs to iommu grouping
+ * @fw_xlate: add FW master IDs to iommu grouping
  * @pgsize_bitmap: bitmap of supported page sizes
  * @priv: per-instance data private to the iommu driver
  */
@@ -196,9 +214,7 @@ struct iommu_ops {
        /* Get the number of windows per domain */
        u32 (*domain_get_windows)(struct iommu_domain *domain);
 
-#ifdef CONFIG_OF_IOMMU
-       int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
-#endif
+       int (*fw_xlate)(struct device *dev, struct iommu_fwspec *args);
 
        unsigned long pgsize_bitmap;
        void *priv;
-- 
2.6.4

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